Many semiconductor devices generate heat which must be dissipated to avoid damage to the device and/or impairment of its operating characteristics. In some devices, the heat generated is sufficiently dissipated by the enclosure, header or leads. Sometimes the device package is mounted on heat sinks including bodies of thermally conductive materials such as, for example, copper and aluminum which dissipate the heat generated by the semiconductor device into the surrounding environment. Such heat sinks may have extruded, machined or formed sheet metal bodies with dissipating fins and the like for conducting heat from the electronic device and dissipating heat into the surrounding environment.
Advances in microelectronics technology tend to develop device chips which occupy less physical space while performing more functions. Conventionally, the chips are packaged in housings which protect the chip from its environment and provide means for input/output communication between the chip and external circuitry. Miniaturization thus results in generation of more heat in less space with less physical structure for removing the heat from the electronic device package. Furthermore, as device packages decrease in size and are adapted for surface mounting on a circuit board or the like, attachment of heat sinks to the device package is further complicated not only by miniaturization of the package itself, but the requirement that heat sinks be secured to the package without causing damage to or electrical shorting between terminal leads extending from the package. Of course, as the size of the package decreases, the number and fragility of terminal leads increases. The size and shape of the heat sink used in connection with any specific electronic device package will vary, of course, with the configuration of the device package, the thermal dissipation requirements and the environment into which the thermal energy must be dissipated.